This boy was stabbed 13 times in a row over a mobile phone in May, a court has recently heard
Lyle Tulloch was stabbed through the heart when he was attacked by two other teenagers at a flat in Elephant and Castle, south east London, in May.
Damien Sobowale, 18, and a 17-year-old youth who cannot be named, rounded up partygoers outside when Sobowale's phone went missing, the Old Bailey heard.
They dragged 15-year-old Lyle round the corner to search him and then he was heard crying out, David Waters QC, prosecuting, said.
A friend of Lyle's is said to have distracted them by pretending he had the phone, then leapt, terrified, from the second floor balcony on to a ledge to escape the knife-wielding Sobowale, jurors heard.
Earlier, Sobowale had gatecrashed the party and reacted angrily when he saw the girl he had arrived with hugging Lyle, the court was told.
Following the row over the phone, he was seen to take a large kitchen knife and put it up his sleeve, Mr Waters said.
The 17-year-old youth was seen stabbing Lyle in the leg as he lay on the ground and later holding a knife dripping with blood, it is alleged.
Sobowale, of Gipsy Hill, south east London, and the other youth, of Deptford, both deny murdering Lyle, who lived with his mother in Peckham.
Both defendants have told police they were at the party that night but left before the murder took place.